Evaluation of dental practitioner habits with occlusal assessment and the clinical application of practical techniques in occlusion, amongst a cohort of participants based in the UK, South Africa, Malta and Malaysia

Abstract Background Currently, there is a lack of data relating to dental practitioners' habits with clinical occlusal assessment and the application of practical techniques in occlusion. Objectives The aim of this study was to investigate habits with clinical occlusal assessment and the practical application of established concepts in occlusion amongst a cohort of international dentists. Methods A piloted questionnaire with 20 statements was distributed by 5 recruiters. The recruiters were based in Malta (1), South Africa (1), Malaysia (1) and the UK (2). Outcomes were analysed using descriptives, chi‐squared and Fisher's exact test. All the analyses were carried out in Stata, Version 12. Significance was inferred at p < .05. Results Four hundred thirty‐five completed responses were included in the sample (response rate, 70.7%). Overall, high levels of agreement were reported with the provision of single‐unit crown and onlay restorations (78.8%) and bridge prostheses (up to 3 units, 77.9%), respectively. One‐third (33.6%) agreed to observing dynamic occlusal relationships during an adult patient dental examination, 40.7% reported using articulators for crown and bridge cases, and 25.1% agreed to taking facebow records. Under half (47.3%) of the dentists expressed dissatisfaction with their undergraduate training in occlusion, with no significant association with the variables of the number of years of experience, the country of practice or being in general practice (p ≥ .226). Conclusion The results indicate a disparity between traditionally taught and applied concepts in clinical occlusion and the undertaking of occlusal assessments and the management of occlusion in clinical practice.


| BACKG ROU N D
The term 'occlusion' has been defined as the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth, or tooth analogues. 1 Static occlusion is used to define those tooth contacts between teeth when the mandible is closed and stationary; the term dynamic occlusion is used to describe the contacts between the teeth when there is a movement of the mandible relative to the maxilla. 2 Dynamic occlusion is influenced by neuromuscular control, by the temporomandibular joints (the posterior determinants) and the occlusal surfaces of the teeth (the anterior determinants). 3,4 Dental practitioners require a clear understanding and should be able to apply the principles of occlusion to enable them to appropriately restore, reposition and replace teeth. 5 The importance of developing adequate knowledge and skills with occlusion is underpinned by the explicit requirements set by some of the governing dental councils for undergraduate teaching in this subject area. 5 There is, however, considerable ambiguity with the topic of dental occlusion. A lack of consensus exists amongst clinicians with the applied concepts and the desired outcomes, especially when undertaking more challenging restorative procedures. 6 The standard of training and education about occlusal principles, the lack of appropriate scientific evidence to support a plethora of opinion-based occlusion-related philosophies with a specific occlusal scheme being superior with the improvement of stomatognathic function 7 and inconsistency with the associated nomenclature with key terms such as 'centric occlusion' and 'centric relation' 8 are some factors which have contributed to this overall confusion.
Previous investigations into the teaching of occlusion at undergraduate level 5,9,10 have identified the need for standardised, clear and contemporaneous teaching guidance. The approach of teaching occlusion by the different disciplines within the profession, sometimes with conflicting ideas and the lack of coordination and consensus between them, may also be a barrier against the effective learning of the accepted concepts in occlusion during undergraduate training. 5 Variations have also been described in the undergraduate teaching hours devoted to occlusion between dental schools based in the UK and Ireland, as well as in the United States. 5,9 O'Carroll et al. 5 also reported differences between the various dental schools with the application of teaching materials and methods, the frequency of taking jaw relationship records and the assessment of competency with occlusion.
Depending upon the type, dental articulators may be used to simulate some or all mandibular movements. This information may be used to facilitate examination of the occlusion and for the fabrication of restorations and prosthesis. There are a variety of dental articulators available in the marketplace. 11 Whilst guidance is available with the selection of an articulator for a given purpose, currently, there is a lack of scientific evidence to support the selection of an articulator. 12,13 The use of semi-adjustable or fully adjustable articulators may provide a more accurate representation of the condylar angle and the relationship between the maxillary plane and the terminal hinge compared with average value articulators or simple hinge articulators. The appropriate use of some articulators may necessitate the taking of a facebow record and/or the taking of a jaw relation. 11 Although a very high level of consistency has been reported with the teaching of the use of the facebows, the same investigation alluded to the presence of variations in obtaining these records in the clinical setting. 5 In addition, the frequency of routinely using semi-adjustable articulators for treatment planning/occlusal assessment and for the execution of care involving single-unit fixed prosthodontics amongst some of the dental schools based in the UK and Ireland has also been described to be inconsistent. 5 However, a former investigation into the use of articulators amongst the UK dental schools reported most of them follow the current guidelines and good practice for articulator selection, with the semi-adjustable type of articulator being the most recommended form of device. 13 The recording of 'occlusion' and 'occlusal abnormality' as 'aspirational' and 'conditional' assessments for all new and recalled dental patient examination appointments, respectively, is advocated by consensus-based dental record-keeping standards, NHS England, 2019. 14 For a new patient attendance (as part of essential practice), the occlusal examination may include an evaluation of the occluding surfaces of the teeth, the incisal angle and molar relationships and the tooth-related guidance during lateral excursive and protrusive mandibular movements. 15 However, information relating to the level of undertaking and recording an occlusal examination in clinical practice is limited. This study presents the results following the use of a piloted questionnaire aimed to investigate the habits of a convenience sample of dental practitioners located in one of four countries with the taking of occlusal assessments, the prescription of a variety of treatments that are likely to directly involve a patient's occlusal scheme, the taking of facebow records and the use of semiadjustable articulators for fixed prosthodontic (crown and bridge) treatments. As a secondary aim, this study also looked at the participant's satisfaction with their undergraduate training in occlusion.

| ME THODS AND MATERIAL S
A convenience sample of dental practitioners was recruited by five student volunteers (the 'recruiters'). The recruiters were based in Malta (DR), Malaysia (BP), South Africa (AB) and the UK (SV and AA). The participant dentists were asked to complete a printed questionnaire, comprising 20 questions. To ensure consistency and accuracy, the questionnaire was piloted amongst a cohort of Year 1 MSc AES students (2019 intake, including 21 dentists). The responses were collected by the second layer of recruiters the same day distribution took place. Responses were subsequently returned to the Recruiter by the electronic scanning of the documents, or in physical format, ensuring the responses remained fully anonymised.
Examples of the statements contained within the questionnaire can be seen in Figure 1. The first four questions (Q1-Q4) related to general demographic aspects, such as the number of years in practice, specialist registration with a dental council (irrespective of the discipline) and presence in general dental practice/the primary dental care setting, and for the UK participants, the arrangements under which they usually provided dental care (state-funded, private or mixed arrangements). Questions 5 to 8 related to the types of dental treatments provided by the participants for adult patients aged 18 years and over. The latter included the direct provision of fixed or removable orthodontic therapy (Q5) and the undertaking of fixed indirect prosthodontic treatments, thus-single-unit crown and onlay restorations, 2-or 3-unit fixed dental bridge restorations and fullmouth rehabilitation (Q6-Q9). A further set of questions (Q9-Q12) related to the recording of aspects of the occlusal assessment during a dental examination for adult dental patients aged 18 years and over, hence, skeletal relationships (Q9) and the recording of some static occlusal relationships-the amount and location of any dental crowding (Q10), the presence of any crossbites (Q11) and the pres-     Depicted by Table 4

| DISCUSS ION
A convenience sample of dentists from four countries reported relatively high levels of agreement with the provision of single-unit Note if a slide exists between the intercuspal position (centric occlusal position) and the retruded contact position (centric relation position) during your dental examination .088 Note the working side contacts during your dental examination .779 Note the non-working side contacts during your dental examination .436 Palpate the muscles of mastication during your dental examination .079 Note if any mobility of the teeth if present during your dental examination .76 Take facebow records for any of your patients <.  The provision of fixed prosthodontic treatment has formerly been reported to be undertaken by 67% of general dental practitioners in South East England 17 ; these outcomes are comparable to the overall sample data from this investigation. Although the restoration of a limited number of occluding surfaces may appear simple, often requiring a conformative approach, in order to help ensure the unwanted alteration of the static and dynamic occlusal relationships pre-and post-treatment, 18 there would be the need to undertake an appropriate appraisal of the dynamic occlusal relationships. 2 The latter would include attempting to identify working and non-working side occlusal contacts. An overview of the factors that may influence the prescription of a confirmative approach, or when this may not be appropriate, the decision with how and when to re-organise the occlusion has been documented in the contemporary literature. 18 In the present study, routine fixed indirect prosthodontic treatments were provided by over three-quarters of the sample; however, only one-third agreed undertaking dynamic occlusal assessments. The precise reasons for a disparity in the numbers of dentists providing single-unit Make a record of the skeletal relationship for your patients' during your dental examination .021 * Record the amount and location of any crowding present in the dentition for your patients .578 Record any crossbite if present .28 Record any anterior open bite if present .228 Note if a slide exists between the intercuspal position (Centric Occlusal position) and the retruded contact position (Centric Relation position) during your dental examination .008 * Note the working side contacts during your dental examination .006 * Note the non-working side contacts during your dental examination .002 * Palpate the muscles of mastication during your dental examination .086 Make a note of any mobility of the teeth if present during your dental examination .554 Take facebow records for any of your patients .148 Use a semi-adjustable articulator for any of your crown and bridge cases .598 Subject of occlusion was satisfactorily covered for you during your undergraduate training .226 *Denotes statistical significance.

TA B L E 5
Association between general dental practice with other measures crown and onlay restorations and those undertaking dynamic occlusal assessments are unknown. Accepting the limitations of this study, this divide may be indicative of the participants' knowledge and practical application of the established concepts in clinical occlusion, 2 the presence of a possible 'disconnect' between the undergraduate prosthodontic curriculum and the general practice of dentistry or the perception of being able to deliver effective and efficient dental care using protocols that are more commonly applied and prescribed in general dental practice. 19 Disparity between the teaching and application of techniques in dental schools and clinical practice in removable prosthodontics have also been described in the literature. [20][21][22] Taking of a facebow record and the use of a semi-adjustable articulator may be indicated with the planning and preparation of fixed (and removable) prosthodontic treatments. 11 This may include the provision of a single-unit crown or onlay restorations. All the dental schools in the UK and Ireland that took part in the study by O'Carroll et al. 5 documented the teaching of the use of a facebow and recording jaw relations, and the use of articulators amongst the UK dental schools has been reported in a different study to closely follow the available guidelines and recommendations. 13 However, a previous investigation showed that only a small percentage of dentists continued to use or prescribed the use of dental articulators after commencing practice. 23 Clark et al. 19  may also be postulated that some of the participants reporting the use of a semi-adjustable articulator may be delegating the responsibility of selecting and using a dental articulator, entirely to their dental technician. A former study into the analysis of the use of dental articulators and dental education and practice reported 10% of dental practitioners did not state the type of articulator they used to mount their casts on. 24 The risks of introducing errors with the patient's occlusal scheme may be assumed to be heightened when undertaking more advanced procedures, such as full-mouth rehabilitation, often involving considerable functional and aesthetic changes. In this investigation, 43.9% of the overall dentists reported providing full-mouth rehabilitation treatments. With approximately one-third of the participants observing dynamic occlusal relationships at the time of undertaking examination and only a quarter attaining facebow records, this may be considered a potential area of significant concern.
With general dental practitioners increasingly providing orthodontic services, 23  Recording of a skeletal assessment during an adult patient dental examination was relatively lower than the proportion of participants recording some static occlusal assessments (52.2% and 78.0% respectively); this difference may be due to skeletal assessment primarily forming part of the clinical orthodontic assessment. 25 The proportion of dentists agreeing to palpate the muscles of mastication during an adult dental patient (58.2%) was comparable to the outcomes of a former investigation performed amongst a group of Swedish general dental practitioners and dental hygienists. 28 Assessment of the temporomandibular joints at rest and during mandibular movement is advised by the available UK-based guidance when performing a routine extra-oral examination for findings such, as clicking, grating, limitation of movement, effusions, pain or tenderness; however, this guidance does not explicitly include the need for palpation of the muscle of mastication, which may be conditional on presentation. 27 As tooth mobility may be the manifestation of a plethora of dental conditions (including occlusal disharmony), despite significant differences between dentists from the various countries represented in the current study sample, it was unsurprising to see high levels of agreement (96.8%) with this statement.
The participants in this study with a greater number of years in practice were also significantly more likely to provide more advanced prosthodontic rehabilitation, attain facebow records and use semi-adjustable articulators (p ≤ .001). Contrastingly, a previous investigation reported more recent graduates (1-5 years in practice) to be significantly more likely to use a semi-adjustable articulator than older graduates (15 years or more in practice). 19 Based on the outcomes of the present study, it would be plausible to assume more experienced dentists having possibly acquired the necessary, knowledge, skills, competence and training, feeling more confident whilst embarking upon more technically challenging clinical cases, with treatment involving planned changes to a patient's occlusal scheme.
As a limitation of this study, the data were not corrected for the variables of age and the complexity of the treatment undertaken. Some significant differences were also observed between the participants from the four countries. Malta-based dentists were significantly more likely to provide orthodontic treatment and more ad- Union. 29 Such dentist to patient ratio may place a greater demand on clinicians to perform more extensive types of dental care and to acquire the necessary skills and competence to enable effective execution of the planned treatment.
Dissatisfaction with the teaching of occlusion at undergraduate level in this study was relatively high (47.3%), with no significant relationship between the number of years of experience or being in general dental practice. Former investigations have also reported poor perceptions of undergraduate education with occlusion, with a lack of adequate training in preparation for clinical practice. 30,31 The latter findings together with the outcomes of the present investigation support the changes described by O'Carroll et al. 5 to include an improvement in the consistency with the teaching of this subject and enhanced coordination between the different disciplines involved with the teaching of occlusion.
The outcomes of this investigation have alluded to some important issues with the application of concepts in clinical occlusion.
However, given the limitations discussed above, there is a clear need for further research in this field, especially in relation to the evidence-base to support occlusal practice.

| CON CLUS ION
The outcomes of this study allude to a disparity between tradition- Subir Banerji contributed to the supervision, writing-review, project administration and editing, formal analysis, software, conceptualisation and project administration.

CO N FLI C T O F I NTE R E S T
The authors did not receive any financial support and declare no potential conflicts of interest with respect to the authorship and/or publication of this article.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available from the corresponding author upon reasonable request.

PEER R E V I E W
The peer review history for this article is available at https://publo ns.com/publo n/10.1111/joor.13358.